1. Field of the Disclosure
This disclosure relates generally to drill bits that include sensors for providing measurements relating to a parameter of interest and the systems for using such drill bits.
2. Brief description Of The Related Art
Oil wells (wellbores) are usually drilled with a drill string that includes a tubular member having a drilling assembly (also referred to as the bottomhole assembly or “BHA”) with a drill bit attached to the bottom end thereof. The drill bit is rotated to disintegrate the earth formations to drill the wellbore. The BHA includes devices and sensors for providing information about a variety of parameters relating to the drilling operations (drilling parameters), behavior of the BHA (BHA parameters) and formation surrounding the wellbore being drilled (formation parameters). Drilling parameters include weight-on-bit (“WOB”), rotational speed (revolutions per minute or “RPM”) of the drill bit and BHA, rate of penetration (“ROP”) of the drill bit into the formation, and flow rate of the drilling fluid through the drill string. The BHA parameters typically include torque, whirl, vibrations, bending moments and stick-slip. Formation parameters include various formation characteristics, such as resistivity, porosity and permeability, etc.
Typically, torque-on-bit and the weight-on-bit (also referred to herein as “weight” or “load”) are estimated using measurements made by sensors disposed on the BHA, i.e., away from the drill bit, which estimates may not be accurate. Therefore, there is a need for an improved apparatus for estimating the torque and weight-on-bit during drilling of a wellbore.